Spot-type disc brake

ABSTRACT

A spot-type disc brake utilizing a floating caliper wherein two brake shoes are applied to opposite faces of the brake disc and an intermediate piece is located between the backing plate of one of the brake shoes and an actuating piston which is maintained in one arm of the floating caliper. The caliper arm is formed with an aperture and the intermediate piece is formed with a projection which cooperates with a depression formed in the brake piston thereby allowing easy removal of the intermediate piece from the disc brake. This in turn allows the easy replacement of the brake shoes which are readily exposed.

United States Patent [451 July 11, 1972 Beller [54] SPOT-TYPE DISC BRAKE[72] Inventor: Hans Albert Beller, Budingerstr, Germany [73] Assignee:lTT Industries, Inc., New York, N.Y.

[22] Filed: Jan. 21, 1971 [21] App1.No.: 108,656

[30] Foreign Application Priority Data Feh. 27, 1970 Germany ..P 20 09260.8

[52] U.S. Cl ..l88/73.6 [51] Int. Cl ..Fl6d 55/00 [58] Field ofSeareh..l88/73.1, 73.3, 73.6

[56] References Cited UNITED STATES PATENTS 3,189,129 6/1965 Burnett..188/73.6 3,357,524 12/1967 Smith ..188/73.6

3,416,634 12/1968 Swift ..l88/73.3 3,486,589 12/1969 Hillegass.......l88/73.6 3,561,572 2/1971 Flegl ..l88/73.6

[ ABSTRACT A spot-type disc brake utilizing a floating caliper whereintwo brake shoes are applied to opposite faces of the brake disc and anintermediate piece is located between the backing plate of one of thebrake shoes and an actuating piston which is maintained in one arm ofthe floating caliper. The caliper arm is fonned with an aperture and theintermediate piece is formed with a projection which cooperates with adepression formed in the brake piston thereby allowing easy removal ofthe intermediate piece from the disc brake. This in turn allows the easyreplacement of the brake shoes which are readily exposed.

6Clains,2Drawingfigures BACKGROUND OF THE INVENTION This inventionrelates to a spot-type disc brake and more particularly to such a brakeutilizing a floating caliper.

Floating caliper spot-type disc brakes normally utilize a brake carrierstraddling the disc of the brake, the carrier being formed with a recessin the central area of the carrier wherein a U-shaped yoke, the floatingcaliper, is positioned. An actuating appliance, for example a piston, isarranged to displace one of the brake shoes in an axial direction sothat it comes into contact with one face of the brake disc and thisdisplaces the caliper in an axial direction, thus bringing the brakeshoe which is placed between the other face of the disc and the otherarm of the yoke into frictional contact with the brake shoe. Spot-typedisc brakes utilizing floating calipers known in the art normallyutilize numerous guiding and retaining elements for the floating calipersuch as levers, lengthening pieces, coil springs, angle-irons, wedges,split pins and screws. Such arrangements may be found for example inGerman Patents 1,211,952 and 1,212,366 and French Patent 88,953. The useof numerous guiding and retaining elements results in a brake which isexpensive to manufacture and quite complicated, and further, a discbrake in which a complicated procedure is required to remove thefloating caliper so that a simple brake pad replacement may be made.

SUMMARY OF THE INVENTION Therefore, the main object of this invention isto provide a spot-type disc brake having a floating caliper which doesnot require numerous guiding and retaining elements to maintain thefloating caliper in its proper position.

It is a further object of this invention to provide such a brake whereinthe floating caliper is easily removed from the brake carrier.

It is a feature of this invention that the force applied to press thebrake pads against the disc are evenly distributed over the backingplates of the brake pads.

According to the present invention, there is provided a spottype discbrake comprising a brake disc having first and second faces, a U-shapedcarrier having first and second legs and a first end portion surroundingsaid disc on three sides, said carrier being formed with a recessbetween said legs, first and second brake shoes located adjacent saidfirst and second faces of said disc, respectively, a floating U-shapedyoke having first and second arms and a second end portion disposed insaid recess and surrounding said disc and brake shoes, actuating meanspositioned in said first arm for actuating said brake and intermediatemeans positioned in said first arm between said first brake shoe andsaid actuating means and responsive to said actuating means for directlyapplying pressure to said first brake shoe.

Further objects and features of this invention will become more apparentby reference to the following description taken in conjunction with theaccompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a cross-sectionalview of a preferred embodiment according to the invention; and

FIG. 2 is a plan view, partially in cross section, of the disc brakeaccording to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2,there is illustrated a spottype disc brake which includes a U-shapedbrake carrier 13 surrounding a brake disc 7. The brake carrier 13 isdisposed to straddle the brake disc 7. Carrier 13 includes therein axialrecesses 18 and 18a with respect to disc 7 serving to axially guide andretain the brake pads 2 and 17 and backing plates 1 2a and 17a to whichpads 2 and 17 are secured. A U-shaped yoke 8, the floating caliper, isdisposed around a portion of brake disc 7, backing plates 2a and 17a andpads 2 and 17 and is floatingly arranged with respect to carrier 13. Thefloating caliper 8 is guided and retained in guiding ledges 11 and 12 ofbrake carrier 13 by means of guiding ledges 9 and 10 of caliper 8 whichare each disposed on opposite sides of and adjacent one peripheralportion of disc 7.

Upon actuation of the spot-type disc brake, the brake ac- I tuatingmeans 4, in this case illustrated as a piston, which is disposed in arm3 or yoke 8, urges intermediate piece 1 into pressure contact withbacking slate 2a which is in turn urged into forceful contact with brakeshoe 2 until the motion of the brake shoe 2 is halted by contact withbrake disc 7. In response to this actuation by piston 4, due to thereaction forces present, projection 14 of arm 15 of yoke 8 is forcedagainst backing slate 17a, and, thus, brake shoe 17 is axially forcedagainst the other side of brake disc 7. Thus, it is seen that during thebraking operation, both brake pads 2 and 17 bear on the brake disc 7 inan axial direction. Intermediate piece 1 has a trapezoidal transversecross-section with respect to disc 7 as seen at 19, and a rectangularcross-section when observed in a transverse direction with respect todisc 7, which allows the brake pads to be made as large as possible andwhich provides for an even transfer of the force of piston 4 to pads 2and 17. Piece 1 is also formed with a projection 20 which fits into, andcooperates with, a groove 6 which is formed in piston 4.

When it is necessary to replace brake pads 2 and/or 17 due to wear, thefloating caliper 8 may be separated from the brake carrier 13 byremoving intermediate piece 1 from the brake by urging it in a directiontransverse to the brake disc thereby separating projection 18 and groove6. Intermediate piece 1 is then lifted out through an aperture oropening 5 which is formed in arm 3 of caliper 8. The aforementionedcarrier guide ledges 11 and 12 and yoke guide ledges 9 and 10 are sodimensioned that with the intermediate piece, which has a widthdimension greater than that of the brake pads, removed, yoke 8 may bemoved in the direction of yoke arm 15 disengaging the ledges. The yokearm 15 can now be removed from brake carrier 13 in a direction radial tothe disc.

The advantages achieved by this invention are thus seen to include thefact that the brake carrier need no longer be unscrewed from the axlestub when the brake pads have to be replaced or when the actuatingappliance, i.e., the piston, needs repair. Brake torque is transmitteddirectly to the brake carrier by the brake shoe and therefore thefloating caliper can easily be disassembled since it has to receive onlythose forces of the piston which act in an axial direction. Afterremoving only a single part, the intennediate piece, the floatingcaliper may be easily removed. Another advantage which will now beapparent is that the shape of the intermediate piece is such that due toits force distributing effect, the brake pads may be made larger thanthey previously could be made.

While the principles of the invention have been described in connectionwith specific apparatus, it is to be clearly understood that thisdescription is made only by way of example and not as a limitation tothe scope of the invention as set forth in the objects thereof and inthe accompanying claims.

lclaim:

1. A spot-type disc brake comprising:

a brake disc having first and second faces;

a U-shaped carrier having first and second legs parallel to said discand a first end portion, said first and second legs and said first endportion surrounding said disc on three sides, said carrier being formedwith a first recess between said legs to receive said disc, a secondrecess in said first leg disposed transverse to said disc and a thirdrecess in said second leg disposed transverse to said disc;

first and second backing plates disposed adjacent said first and secondfaces of said disc;

first and second brake shoes secured to said first and second backingplates, respectively, in braking association with said first and secondfaces of said disc, respectively;

said first backing plate and said first brake shoe being received insaid second recess for movement axially with respect to said disc andsaid second backing plate and said second brake shoe being received insaid third recess for movement axially with respect to said disc;

a floating U-shaped yoke having first and second arms and a second endportion, said yoke being disposed around a portion of said disc, andsaid back plates and said brake shoes;

actuating means positioned in said first arm for actuating said brake;and

intermediate means having a surface parallel to said disc coextensivewith said first back plate, said intermediate means being positioned insaid first arm between said first backing plate and said actuatingmeans, said intermediate means being responsive to said actuating meansfor directly applying pressure to said first backing plate and, hence,said first brake shoe.

2. A spot-type disc brake according to claim 1, wherein 'the first armis formed with an aperture therein, said aperture being so located as toallow said intermediate means to be removed therefrom in a directionparallel to said disc.

3. A spot-type disc brake according to claim 2, wherein said actuatingmeans is formed with a fourth recess therein; and

wherein said intermediate means further comprises a projection thereon,said projection being positioned to engage said fourth recess.

4. A spot-type disc brake according to claim 3, wherein saidintermediate means has a dimension in a direction transverse to saiddisc greater than the corresponding dimension of each of said brakeshoes and a trapezoidal cross-section in said transverse direction, thecross-section of said intermediate means looking in said transversedirection being rectangular.

5. A spot type disc brake according to claim 4, wherein said yoke isformed with a first pair of guide ledges; and

wherein said carrier is formed with a second pair of guide ledges, saidyoke ledges being retained by said carrier ledges. l

6. A spot-type disc brake according to claim 5, wherein the dimension ofsaid first and second pairs of ledges in a transverse direction withrespect to said disc is such that they may be separated by displacingsaid yoke a distance corresponding to the transverse dimension of saidintermediate means.

1. A spot-type disc brake comprising: a brake disc having first andsecond faces; a U-shaped carrier having first and second legs parallelto said disc and a first end portion, said first and second legs andsaid first end portion surrounding said disc on three sides, saidcarrier being formed with a first recess between said legs to receivesaid disc, a second recess in said first leg disposed transverse to saiddisc and a third recess in said second leg disposed transverse to saiddisc; first and second backing plates disposed adjacent said first andsecond faces of said disc; first and second brake shoes secured to saidfirst and second backing plates, respectively, in braking associationwith said first and second faces of said disc, respectively; said firstbacking plate and said first brake shoe being received in said secondrecess for movement axially with respect to said disc and said secondbacking plate and said second brake shoe being received in said thirdrecess for movement axially with respect to said disc; a floatingU-shaped yoke having first and second arms and a second end portion,said yoke being disposed around a portion of said disc, and said backplates and said brake shoes; actuating means positioned in said firstarm for actuating said brake; and intermediate means having a surfaceparallel to said disc coextensive with said first back plate, saidintermediate means being positioned in said first arm between said firstbacking plate and said actuating means, said intermediate means beingresponsive to said actuating means for directly applying pressure tosaid first backing plate and, hence, said first brake shoe.
 2. Aspot-type disc brake according to claim 1, wherein the first arm isformed with an aperture therein, said aperture being so located as toallow said intermediate means to be removed therefrom in a directionparallel to said disc.
 3. A spot-type disc brake according to claim 2,wherein said actuating means is formed with a fourth recess therein; andwherein said intermediate means further comprises a projection thereon,said projection being positioned to engage said fourth recess.
 4. Aspot-type disc brake according to claim 3, wherein said intermediatemeans has a dimension in a direction transverse to said disc greaterthan the corresponding dimension of each of said brake shoes and atrapezoidal cross-section in said transverse direction, thecross-section of said intermediate means looking in said transversedirection being rectangular.
 5. A spot type disc brake according toclaim 4, wherein said yoke is formed with a first pair of guide ledges;and wherein said carrier is formed with a second pair of guide ledges,said yoke ledges being retained by said carrier ledges.
 6. A spot-typedisc brake according to claim 5, wherein the dimension of said first andsecond pairs of ledges in a transverse direction with respect to saiddisc is such that they may be separated by displacing said yoke adistance corresponding to the transverse dimension of said intermediatemeans.